The present invention relates to a method of controlling the quality in the production of a plurality of yarns in a corresponding number of processing stations which are similar to one another.
For the production of synthetic filament yarns, it is customary to employ production lines, which consist of a plurality of similar processing stations, each of which realizes similar and simultaneously occurring processing steps. Each of the similar processes is determined by a plurality of influence variables, the sum of which defines the quality of the yarn produced at each processing station.
A method of monitoring the quality in the production of a plurality of yarns is known from EP 0 439 106 A1, wherein in the production of a synthetic filament yarn that is textured by the false twist method, the individual processing station is monitored, in that the reference signal is obtained from measuring the process parameters of a plurality of production stations.
The simplest form of evaluation consists of forming a mean value, which rates all processing stations equally. The mean value of all processing stations will then allow an indication of the quality of the entire process or product to be obtained. However, as an absolute value, this indication is not necessarily correct, but is dependent on the condition of the processing stations. If the course of the process in all processing stations is shifted uniformly relative to the actually intended condition, the formation of the mean value will not result in any significant deviations of the processing stations from one another. As a result, the uniformity of the mean value appears to be indicative of the presence of a desired course of process, whereas the entire process itself does not proceed in a desired manner.
It is the object of the present invention to provide a method which achieves, with reasonable measuring and evaluation resources, a substantially uniform and equally good control of the production processes in all stations of a multiposition textile machine.